This invention generally relates to remote control of a flow control valve, which provides valve spool displacement proportional to a remote manual control signal.
In more particular aspects this invention relates to a digital valve spool drive, which moves the valve spool in discrete steps, in response to a remote manually controlled digital signal.
In still more particular aspects this invention relates to a digital valve spool drive of a control valve, in which the pressure differential acting across the spool may be controlled by the positive and negative load compensators.
The great majority of electronic computing circuits, using micro-processors and computers, use a digital output signal. Digital valve spool drive, directly responding to such a signal, may be adapted to manual control. Such an adaptation presents a difficult problem, since not only the valve spool must be moved against considerable inertial, frictional and flow force resistance, but the valve spool travel must be proportional to the remote manual control signal, transmitted in digital form.